Vpliv hitrosti gibanja zraka na kinetiko konvekcijskega sušenja bukovine (Fagus sylvatica L.)

Straže, Aleš (author), Gorišek, Željko (author)

Raziskava primarno proučuje kinetiko konvekcijskega sušenja bukovine (Fagus sylvatica L.) v svežem stanju ter učinke procesnih pogojev v nadaljevanju sušilnega procesa. Uporabili smo sveže radialno orientirane preizkušance, debeline od 6 mm do 24 mm (ΔL = 6 mm). Enosmerno konvekcijsko sušenje smo izvedli pri konstantni temperaturi 30 °C in 85 % relativni zračni vlažnosti z variiranjem hitrosti gibanja zraka od 0,6 m/s do 7,6 m/s. Med procesom smo gravimetrično določali lesno vlažnost in vlažnostni gradient. Sušilna hitrost je v svežem stanju lesa splošno naraščala s povečevanjem hitrosti gibanja zraka. V začetnem stanju je v kratkem intervalu faza relativno konstantne sušilne hitrosti dosežena le pri tanjših preizkušancih (≤ 12 mm) pri hitrostih gibanja zraka do 2,5 m/s. Višja hitrost gibanja zraka (> 2,5 m/s) pri sušenju lesa v svežem stanju sicer poveča masni tok vode, a hkrati povzroči velik podpovršinski vlažnostni gradient. Posledično kinetiko sušenja v nadaljevanju determinira značilen notranji difuzijski upor, kar bistveno podaljša celotni proces

• Language: Slovenian
• Keywords: les, sušenje, hitrost gibanja zraka, masni tok vode, vlažnostni gradient
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Publication date: 01.01.2011
• Year: 2011
• Number of pages: Str. 317-322
• Numbering: Letn. 63, št. 8/9
• PID: 20.500.12556/RUL-136595
• UDC: 630*847
• ISSN on article: 0024-1067
• COBISS.SI-ID: 1965961
• Publication date in RUL: 12.05.2022

STRAŽE, Aleš and GORIŠEK, Željko, 2011, Vpliv hitrosti gibanja zraka na kinetiko konvekcijskega sušenja bukovine (Fagus sylvatica L.). Les [online]. 2011. Vol. 63, no. 8/9, p. 317–322. [Accessed 18 May 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=136595

Record is a part of a journal

• Title: Les
• Shortened title: Les
• Publisher: Zveza društev inženirjev in tehnikov gozdarstva in lesarstva Slovenije, Zveza društev inženirjev in tehnikov gozdarstva in lesarstva Slovenije, Biotehniška fakulteta, Oddelek za lesarstvo, Založba Univerze, Biotehniška fakulteta, Oddelek za lesarstvo, Založba Univerze
• ISSN: 0024-1067
• COBISS.SI-ID: 13940224

Secondary language

• Language: English
• Title: Influence of air velocity on kinetics of kiln drying of beechwood (Fagus sylvatica L.)

Abstract

For determination of suitable process conditions at drying of European beechwood (Fagus sylvatica L.) the unidirectional drying kinetics, with an emphasis of free water removal was researched. We used radially oriented sapwood specimens, having thickness from 6 mm to 24 mm (ΔL = 6 mm). Series of conventional drying processes were carried out in the laboratory tunnel drier at constant climate (T = 30 °C, φ = 85 %) with various air velocities from 0.6 m/s to 7.6 m/s. During the drying, moisture content, moisture gradient and moisture flow were gravimetrically determined at successive time intervals. Drying rate generally increased by rising of the air velocity and decreased by increasing of wood thickness. Relatively constant drying rate was present at thinner specimens (≤ 12 mm) in a short time interval of the initial stage of the process, when low air velocity was used (≤ 2.5 m/s). Increasing of the air velocity (> 2.5 m/s) lead to early irreversible reduction of initial moisture flow and to the transition into the period of significantly falling drying rate, where the internal mass resistance predominated. The diffusion barrier was induced at too fast free water removal which controlled further drying rate and significantly prolonged the process in continuation

• Keywords: wood, drying, air velocity, water mass flow, moisture gradient